Tri-mAb is less effective against orthotopic kidney cancer than it is against subcutaneous tumors. Mice were injected with Renca cells either subcutaneously (s.c.) (2 × 105) or intrakidney (i.k.) (1 × 105). On day 10 after tumor injection, some groups of mice received Tri-mAb treatment consisting of 100 μg each of anti-DR5, anti-CD40 and anti-CD137 on days 10, 13 and 17. Other groups of mice received control treatment consisting of isotype control antibodies (MAC4, rat IgG2a; UC8-1B9, hamster IgG) or were left non-treated (NT), and survival monitored. Two representative experiments of three are shown A and B. Control refers to non-treated in panel A and MAC4 rat IgG2a and UC8-1B9 isotype controls for panel B. Survival of s.c. tumor-bearing mice greater than mice with kidney tumors, P2 = 0.034 for pooled data from A and B, Log-rank Test. (s.c. = subcutaneous tumor; i.k. = intrakidney tumor).